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Biomedical subjects

I R Duce

Publications and source records attributed to I R Duce.

7 recordsLinked to original sources
PubMed1977

An ultrastructural classification of the neuronal cell bodies of the rat dorsal root ganglion using zinc iodide-osmium impregnation.

Zinc iodide-osmium (ZIO) impregnation of rat dorsal root ganglia differentially stained various elements in the neuronal cells, particularly their Golgi bodies. On the basis of this differential ZIO staining dorsal root ganglion neurones have been classified into seven types. The ultrastructure of these is described and the numbers of each type in the L4 dorsal root ganglion have been determined. Prolonged nerve stimulation did not change the relative numbers of the different cell types suggesting that none of the differences between cell types represents differences in their state of activity. The possibility is discussed that differences in morphology may reflect differences in neurotransmitter function.

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PubMed1977

The formation of free axonal sprouts from a dorsal root ganglion-nerve preparation maintained in organotypic culture, and the effects of demecolcine.

Nerve-ganglion preparations from rat dorsal spinal nerve roots were maintained in organotypic culture for 20 h. Free axonal sprouts formed at the cut tips. Clear and dense-core vesicles, mitochondria and smooth endoplasmic reticulum accumulated in the axons for a distance of 500 micronm behind the cut, as has previously been described in dorsal roots sectioned in vivo. Sprouting did not occur in dorsal roots maintained in culture without their ganglia attached. Sprouting was also prevented by demecolcine (3 x 10(7) M) which reduced the number of microtubules in non-myelinated, small myelinated and large myelinated axons to respectively 45, 30 and 20% of control values. The sprouts contained several types of vesicle including small clear vesicles, large and small dense-core vesicles and flattened vesicles. The possible relevance of the vesicles to transmitter mechanisms in these neurones is discussed.

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PubMed1976

A light and electron microscope study of changes occurring at the cut ends following section of the dorsal roots of rat spinal nerves.

Rat dorsal spinal nerve roots were cut; 20 h later the axons in the vicinity of the cut were examined by light and electron microscopy. The changes in the cut tip distant from the ganglion were largely degenerative. On the ganglionic side of the cut a cap of free unmyelinated sprouts was formed. These sprouts contained clear and dense-core vesicles 40-150 nm in diameter, smooth endoplasmic reticulum and mitochondria. Some of the unmyelinated sprouts were extensions of myelinated axons, others arose from myelinated axons by lateral budding. In both myelinated and non-myelinated axons there was an accumulation of mitochondria, tubulo-vesicular smooth endoplasmic reticulum and large and small dense-core vesicles for a distance of approximately 500 mum behind the tip. Dense-core vesicles were more common in non-myelinated axons than in their myelinated counterparts. In areas of intense accumulation the non-myelinated fibres were grossly swollen and distorted. The myelinated axons and some of the sprouts contained an unusual type of mitochondrion. The similarity between these sprouts and pre-synaptic terminals is discussed.

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PubMed1976

A scanning electron microscope study of the development of free axonal sprouts at the cut ends of dorsal spinal nerve roots in the rat.

Rat dorsal spinal nerve roots were cut and the tip on the ganglionic side of the cut was examined by scanning electron microscopy at 0, 7, 20 and 48 h after operation. Seven hours after cutting, free axonal sprouts had started to protrude from the cut end of the nerve. After 20 h the free sprouts were more profuse than at 7 h but were smaller and had a rougher surface. At both 7 and 20 h many of the sprouts consisted of a stalk 2-7 mum in diameter with a bulbous end 5-20 mum in diameter. A few branching sprouts were seen. At 48 h the sprouts were shrunken with a deeply furrowed surface. The significance of the surface structure of the sprouts is discussed.

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